Plasma cholinesterase polymorphism in Down's syndrome.

The plasma cholinesterase variants in 80 patients having Down's syndrome have been examined and compared with a random control sample of individuals domiciled in the same area. Neither a change in frequency of known C5+ variant nor any new variant has been found in the electrophoretic studies. A highly significant increase in frequency of the fluoride resistant gene as well as a significant decrease in frequency of the atypical gene has been found in the Down's syndrome individuals. This altered distribution of the rare phenotype of plasma cholinesterase in mental illness may lead to a useful diagnostic acid in genetic counselling.     

Plasma cholinesterase studies on south-eastern Bantu of Mozambique.

Blood samples from four Bantu tribes in South-East Mozambique have been phenotyped for the plasma cholinesterase variants of the E1 locus. A control roup of 153 Portuguese residents in Mozambique have also been phenotyped. The frequencies of both the E1a and E1f genes in the Portuguese population is very similar to those in other Caucasian populations. The absence of the E1a gene in the four Bantu tribes provides more evidence of the rarity of this gene in Negroid populations. There is an increased frequency of E1f gene in all tribes as compared with previous surveys. The Ronga and Bitonga tribes have similar E1f frequencies of 0.047 and 0.048, respectively. The Shangana has an E1f frequency of 0.060, and the corresponding figure for the Chopi tribe is 0.089. The latter is the highest recorded frequency for this gene. The results give some support to the doubts concerning the affiliation of the Chopi tribe.     

Sex differences of plasma cholinesterase in the rat.

Plasma cholinesterase activity of adult female HAN-Wistar rats was found to be 5.5-fold higher than that of adult male rats kept under constant specified pathogen-free (SPF) conditions up to their 870th day of life.     

Hydrolysis of cocaine in human plasma by cholinesterase.

Hydrolysis of cocaine to ecgonine methyl ester in human plasma is mediated by cholinesterase. Cocaine hydrolysis by plasma is blocked by DFP and eserine and partially inhibited by fluoride. Highly purified cholinesterase from human plasma when diluted to the same benzoylcholine hydrolyzing activity as human plasma, shows the same rate of cocaine hydrolysis as human plasma. There was no detectable enzymatic conversion of cocaine to benzoyl ecgonine in plasma.     

Histochemical investigations of Rotifera Bdelloidea. I. Localization of cholinesterase activity

Summary Cholinesterase activity has been investigated in Rotifera Bdelloidea (Philodina roseola, Philodina tubercolata, Rotaria rotatoria and other unidentified species) by histochemical methods andin vivo observations. Parallel histological studies have been carried out. The enzyme specificity was tested by employing different substrates and inhibitors. The effectsin vivo of tubocurarin, bungarotoxin and acetylcholine were also observed. Acetylcholinesterase activity is localized in the nervous and muscular tissues, in sensory organs and in all the ciliated cells. Secretory cells (subcerebral, salivary and pedal glands) and gonad cells (nuclei of the syncytial vitellarium and follicular layer, oocytes and eggs) show both acetyl-and butyrylcholinesterase activities. The effectsin vivo of cholinesterase inhibitors, as well as those of tubocurarin, bungarotoxin and acetylcholine, are consistent with the histochemical results, indicating a cholinergic system of transmission and acetylcholinesterase, as well as butyrylcholinesterase, activity.This paper is dedicated to my master, the late Professor António Minganti.